Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °
You are not logged in.
#1 2012-11-24 11:25:19
- infinitebrain
- Full Member
Offline
Probability Question
Six boys and twelve girls are in a senior class.Half the boys and 25% of the girls wear glasses.What is the chosen probability that a student chosen randomly is a boy,wears glasses,or both? I know the answer is 50%, but could someone could explain to me clearly how you get that answer? Thanks!
The best thing about life is you don't know what to expect
#2 2012-11-24 13:19:58
- Agnishom
- Super Member
Offline
Re: Probability Question
Probability that the chosen one is a boy =
Probability that the chosen one wears glasses =
Probability that the chosen one is both a boy and wears glasses = (Probability of being a boy) * (Probability of a boy to wear glasses) =
Last edited by Agnishom (2012-11-24 13:22:47)
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'The whole person changes, why can't a habit?' -65
#3 2012-11-24 13:35:03
- infinitebrain
- Full Member
Offline
Re: Probability Question
Thank you Agnishom! 
Sorry, I went back to look at the documents and it said A is correct, which is 16 2/3%! 
The best thing about life is you don't know what to expect
#4 2012-11-24 13:41:15
- Agnishom
- Super Member
Offline
Re: Probability Question
You are Welcome, @infinitebrain
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
'The whole person changes, why can't a habit?' -65